The Spatial Distribution Characteristics of Selenium Content in Tea Leaves from Major Tea-producing Areas in Yunnan
Selenium is an essential trace element for the human body,and dietary intake is a good way to supplement selenium.Tea is a food with great potential for selenium supplementation with has a good enrichment ability for selenium.In this study,the selenium content in tea leaves from the main tea-producing areas in Yunnan Province(central Yunnan,western Yunnan,southern Yunnan,and northern Yunnan)was determined using the"open digestion-ICP-MS"method.The results showed that the average selenium content in Yunnan tea leaves was 73.1μg/kg,with a coefficient of variation of 126.68%.The average selenium content in tea leaves from different tea-producing areas ranked from highest to lowest as follows:central Yunnan(94.52 μg/kg)>southern Yunnan(72.55 μg/kg)>western Yunnan(70.65 μg/kg)>northern Yunnan(34.75 μg/kg).The proportions of selenium-rich tea leaves(selenium content between 200-4 000 μg/kg)in central Yunnan and southern Yunnan were 6.89%and 1.59%,respectively,indicating the potential for developing selenium-rich tea gardens in these regions.The correlation analysis between the selenium content in tea leaves and environmental and climatic factors(soil background value,temperature,rainfall,sunshine,etc.)showed a certain correlation between the selenium content in tea leaves and soil background values,but no correlation with other climatic factors.There were minor differences in the average selenium content in tea leaves processed by different methods.Compared to other types,black tea had higher and more stable selenium content,indicating that the selenium content in tea leaves is less affected by processing methods and mainly influenced by the maturity of the fresh tea leaves.
Yunnan tea-producing areasseleniumteaspatial distribution characteristics
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